1. Field
The present disclosure relates generally to manufacturing components and in particular to a method and apparatus for shaping materials for components. Still more particularly, the present disclosure relates to a method and apparatus for forming waves in sheet metal.
2. Background
Corrugating sheet metal involves forming features, such as wrinkles, folds, alternating ridges and grooves, or waves in sheet metal. Although the corrugation of sheet metal to form wave shapes can create many forms, a common shape consists of circular arcs either directly connected to each other or connected by straight segments. This shape is often named after the mathematical sine wave, even though the actual shape may be slightly different. This type of process may be used to form various components. These components include those for use in aircraft. For example, a very efficient structural beam may be made by welding sheet metal flanges to a corrugated web.
Corrugated sheet metal may form efficient structural components that are capable of supporting high sheer loads or pressure loads. This high sheer load capability may be aided by the resistance to buckling of the corrugated sheet metal within the beams relative to standard flat webs. This corrugated sheet metal may form a web for a beam or some other support structure.
Support structures, such as beams, may be made from various materials including high strength lightweight materials, such as titanium alloy Ti 6Al-4V. Using titanium alloys may provide a high strength to weight ratio for aircraft components. These types of beams may be used in aircraft components such as floor beams, wing spars, and stabilizer spars. The use of this type of beam has been limited in part because of the time and expense in making these wave shaped forms. These wave shaped forms of sheet metal used in beams or other components are also referred to as corrugated webs or just webs.
Past processes for creating these corrugated webs for aircraft structures involve using a brake press to form each bend or wave in the corrugated web one at a time. This type of process also may require indexing holes for pre-punching in the strip of metal to accurately index each bend. These index holes may be used to properly space the waves while the strip stress is relieved in a furnace to obtain the desired wave dimensions in the web.
Brake forming, however, uses a brake press and is a slow and expensive manual process. As a result, this process is not especially useful for commercial production of aircraft. Further, the use of index holes formed into the metal is undesirable. As a result, the index holes are formed in excess metal that is later trimmed off of the web. Additionally, a stress relief step also adds to the cost and time needed to produce webs for use in aircraft components.
Another currently used process for forming waves or corrugations in sheet metal materials employs gears to form the waves. This type of process involves passing sheet metal between two gears with the gears engaging the sheet metal to form the wave shapes for the web. This type of technology, however, is typically used for forming materials, such as mild steel, soft aluminum, or cardboard.
The gear forming process requires different gears to accommodate different sheet metal gages or to produce waves of different shapes or sizes. Current gear forming equipment does not allow easy changing of the forming gears.
Another currently used process for creating waves in a material utilizing hot die forming or hot sizing. Hot die forming is a process for making accurate titanium sheet parts. In this process, a pre-formed or partially formed item may be placed between two fitted dies. This configuration is heated to around 1350 degrees Fahrenheit and pressed for about ten minutes. At this time and temperature, the material softens and creeps at an amount that is sufficient to set the dimensions without undesired spring back.
This type of process, however, is costly because the process requires a hot press with service and maintenance expenses. Additionally, the dies also are made from exotic high-temperature materials, which add to the cost. Further, die maintenance costs are present as well as the process being relatively slow as compared to the gear forming processes.
Therefore, it would be advantageous to have a method and apparatus that overcomes the problems described above, as well as possible other problems.